Ever tried the type 0 toroids?

[sendler]

Originally Posted by stinius

Bob Cordell about classD

here

and

here

Cheers
stinius

Wow! Bob Cordell likes class D air toroids. Great link stinius.

[5th element]

I might be missing the point, but couldn't you just buy a standard ferrite core and saw a gap in it?

[Nikolas Ojala]

Originally Posted by 5th element

I might be missing the point, but couldn't you just buy a standard ferrite core and saw a gap in it?

If you want to use a gapped ferrite core, then better to buy such core that you don't need to saw. There are plenty of them.

[Radian]

I suggested this already in the other thread but it fits better here.

The Wurth coils are the best coils I tried so far for my system with the Shure 2x100 amps.
They are better than 10uH air cores that I took out of my Charlize and
many others that I bought and wound.
For the price you should at least try them in your system.
They do equally well with my full Horn-system, KRK monitors or Fonken.

Greets,
Klaus

[sendler]

Thanks for the tip Klaus. As you have found the output coil is the key that can unlock the superiority of class D. I ordered the Wurths that you like from Digikey and will report at the Sure 2X100 thread here.
.
Sure Electronics New Tripath Board tc2000+tp2050
.

[Don Jerry]

How to install a Wurth coils on a board that uses the toroids?
The Wurths XXL are SMD while the toroids are soldered "through-board".
Is it possible to install the Wurth coils raised up a little with rheophores?
Any drawbacks of this solution?
Thanks, bye!

[Don Jerry]

Originally Posted by sendler

The toroid air cores do exhibit much better containment than the cylinders but still leak a little more than the T106-2 cores. Even the type 2 cores are not as silent as you might think. Are they leaking from the leads? The original little smd shielded bobbins were dead silent. Anyone care to try their amp and report back? Maybe all of our hand wound cores leak a little. I am listening with an AM radio tuned between stations to the switching frequency. Turn your amp on and off and listen to the difference.

Once a board is installed in a metal case, isn't that shielded? So the emi pollutions shouldn't be anymore a problem. What do you think about?

[sendler]

Originally Posted by Don Jerry

How to install a Wurth coils on a board that uses the toroids?
The Wurths XXL are SMD while the toroids are soldered "through-board".
Is it possible to install the Wurth coils raised up a little with rheophores?
Any drawbacks of this solution?
Thanks, bye!

Yes the Wurth XXL coils are my favorite as the sonics are very close to an air core with some advantages of much smaller size and less EMI. Much better sound than the undersized type 2 cores that everyone uses. More loss than the air cores though so battery users will find less run time. Just add some solid core wires to the Wurth coils and fit them down to the board as best as possible.

[Conrad Hoffman]

Originally Posted by Nikolas Ojala

If you want to use a gapped ferrite core, then better to buy such core that you don't need to saw. There are plenty of them.

IMO, the properties of a high perm ferrite with a gap are different than a lower perm ferrite unless you really get lucky. I do some work with high Q resonant inductors (non-audio) and nothing can beat the gapped ferrite for maintaining the Q under power.

Sawing a gap is easier than one might think. I use a thin copper or brass wheel with some silicon carbide grit slurry in a dish on the bottom, and the part gravity fed from the top. There are also inexpensive diamond saws if you want to go that route. Check the lapidary supply places. If you're paying more than $10 for a nice 4" diamond saw, you haven't found the right place.